1. Field of the Invention
This invention relates to a data communication system, and particularly to a method and system for synchronizing two end terminals using beacon synchronization in a wireless local area network.
2. Description of the Related Technology
Recently a variety of computer network systems have been widely used. Such network systems include a local area network (LAN), a wide area network (WAN), a wireless local area network (WLAN), a wireless personal area network (WPAN), a general packet radio service (GPRS) network and other wireless network systems. The network systems allow communication between various end terminals such as a personal computer (desktop, laptop, and palmtop), a mobile phone, or other portable communication devices. It is typical that such network systems include at least one bridge element or hub such as an access point (or access node) where user traffic enters and exits a communications network. Among the network systems, a WLAN is a network that allows access to, for example, the Internet without the need for any wired connections to the user's device (end terminal). By using a WLAN, a user can wirelessly send email, web browse and print documents via local printers, etc.
A WLAN is defined in the IEEE 802.11 standard. The 802.11 standard defines two modes: infrastructure mode and ad hoc mode. In infrastructure mode, the wireless network includes at least one access point in data communication with the wired network infrastructure and a set of wireless end terminals or stations. Since WLANs typically require access to the wired LAN for services (file servers, printers, Internet links, etc.), they mostly operate in infrastructure mode. In ad hoc mode, which is also called peer-to-peer mode, a set of 802.11 wireless stations communicate directly with one another without using an access point or any connection to a wired network. This mode is useful for quickly and easily setting up a wireless network anywhere a wireless infrastructure does not exist, such as a hotel room or an airport, etc. Whether the system operates either in infrastructure mode or ad hoc mode, the synchronization of communication data between the two end stations is an important issue in WLAN as in other communication systems.